The present invention relates in general to complexes referred to as xe2x80x9cself-adhesivexe2x80x9d complexes composed especially of a nonstick silicone matrix and of an adhesive coating.
This type of complex is generally intended for use where the crosslinked or cured silicone matrix is affixed to a substrate so as to make it nonstick with respect to the adhesive. This type of complex is especially applicable in the field of adhesive protective papers, labels, decorative papers and adhesive tapes.
The silicone oils or resins that have been proposed in order to obtain this type of coating having nonstick properties derive in general from cationic and/or radical crosslinking systems. More particularly, they are monomers, oligomers and/or polymers of the polyorganosiloxane kind comprising functional and reactive radicals capable of forming intrachain and interchain bridges. These systems result, after crosslinking, in nonstick coatings which form complexes called xe2x80x9cself-adhesivexe2x80x9d complexes with adhesives, which are applied to their surface after siliconizing.
An essential property of these silicone/adhesive complexes is that they allow an easy release of the adhesive from the silicone coating when they are used.
Depending on the nature of the applications contemplated for this type of complex, it is desirable to be able to vary the release force needed to separate the silicone coating from the adhesive coating.
This release force may in this case be quantified. Although its values may vary significantly depending on the measurement method adopted, overall it can be characterized as follows for a low release rate, that is to say of around 30 cm/min, and using the FTM3 method:
a release force of less than 15 g/cm is regarded as low;
a release force of greater than 15 g/cm and less than 70 g/cm is regarded as moderate; and
a release force of greater than 70 g/cm and preferably less than 200 g/cm is regarded as high.
It is an object of the present invention specifically to provide a silicone/adhesive complex whose release force may be adjusted as required and preferably to a value lying within the abovementioned range, namely between 15 g/cm and 200 g/cm.